The present invention relates to a linear image sensor suitable for an image scanner to effect reading of image, used in a facsimile machine for transmitting image information and in a desk-top-publishing machine.
Recently, there have been marketed various types of information processing instruments such as facsimile machine for transmitting image information and desk-top-publishing machine for editing image. In order to expand market for consumer use, it is necessary to reduce cost of the image sensor used in these instruments.
As shown in FIG. 3, the known image sensor in the prior art is comprised of a plurality of photoelectric conversion elements S.sub.n, S.sub.n+1 --for converting image information into electric signals switching elements SW.sub.n, SW.sub.n+1 --for feeding outside the electric signals obtained from the respective photoelectric conversion elements, reset gate elements RG.sub.n, RG.sub.n+1 --each coupled to the corresponding photoelecric conversion element for resetting the same to the initial state after feeding out the electric signal representative of image information, and a scanning circuit composed of flipflops FF.sub.n, FF.sub.n+1 -- for sequentially driving these switching elements and the reset gate elements.
As noted above, the demand for cost reduction increases while image information processing instruments have been widely spread. Especially, it is most necessary to reduce the cost of image sensor which constitutes the image information input unit of these instruments.